Method and apparatus for surfacing plate glass



J. H. FOX

METHOD AND APPARATUS FOR SURFACING PLATE GLASS Filed July 21, 1927 3 Sheets-Sheet 1 INVENTOR MAL/7 J. H. FOX

METHOD AND APPARATUS FOR SURFACING PLATE GLASS Filed July 21, 1927 s Sheetg-Sheet 2- 4 i S. & s,

INVENTOR JPH. FOX

AND APPARATUS 1 0R sunmcme PLATE cuss Filed July 21. 1927 METHOD 3 Sheets-Sheet 3 7 i Q W difiiculty and permit Patented Get. 9,

UNITED STA JOHN H. FOX,

TEST

on PITTSBURGH, PENNSYLVANIA, 'AssIGN'oa To PI TSBURGH PLATE GLASS CQMPANY, A CORPORATION or PENNSYLVANIA. I Y w I insane PATENT; OFFICE-- METHOD ANnAPrARATUs FOR SURFACING PLATE GLASS.

,7 Application filed July 21,

The invention relates to an improvement in the so-called straightawayor continuous systemfor grindingand polishing plate glass, wherein the sheets of glass carried upon tops of a series of tables or cars are carried beneath a plurality of grinding. and polishing machines. The invention has-for its princi pal object, the provision of aparatus and pro-. cedure whereby the time andlabor loss incident to the storing and handling. of large quantities ofplates atthe starting end the. series of machines is avoided. With straight away surfacing apparatus, as heretofore pro- I of a series of grindingmachmes, all located posed, it has been necessary to surface a large number of sheets on one side only, and then discontinue this procedure, and surface the accumulated plates onthe other side. "This has been necessary, because thesheets carried beneath the grinding and polishing runners must obviously be of substantially the same thickness, otherwise, the breakage wouldvbe v excessive, due to the runners operating over a surface of varying level, and dueto the factthat the grinding runners would exert an undue, pressure on the thicker sheets. The present invention is designed to overcome this the surfacing, at one and the same time, of sheets which have not been surfaced on either side and of'sheetsi which have been surfaced on one side, so

that-the requirement for storing large quanv tities of either kind of sheets at the starting end of the series of machines is avoided.

Briefly stated, this is acomplishedby us ing tables of two different heightspone kind of tables having their top surfaces at a level different from that of the other lrind of table by an amount equal to the average thicknessof glass which is cut away during the passage ofthe glass beneath the se'ies of grinding and polishing machines. For instance, if the average amount of glass which is cut away'by the surfacing operation is onethirty-second of .an inch, the tables which are to carry the sheets which have been surfaced one side will have their upper surfaces onethirty-second of an inch higher than the ,tables which are to carry the glass which is rough on both sides. The two kinds of sheets with their appropriate, tables may alternate in the train of tables, or they may be mixed indiscriminately, all that is necessary being,

192.7. Serial no 207,407.

quirement for any ektensivestorage space at the starting end of the system .18 thus-avoided. One form. of apparatus for practlcing the method is shown in the accompanying drawings, wherein: V a

Figure 1 is a plan viewshowing the general arrangement of the apparatus. Fig. 2 is a longitudinal section. on the line 11-11 of Fig. 3. Fig. 3 is a section on the lineIII III of Fig 2. And Fig. 4; is an enlarged ver.-.

tical section through tWOrOf the cars ortables at their meeting ends Referring to the drawings, 1 and Qare two above the track 3, and 4 and 5 aretwo of a series of polishing machines, also located above the track 3. The'grinding machines comprise the-runners 6, '6. faced withfiron grinding surfaces and driven from the motor 1 grinding runnersare supplied with a'mix-' ture of abrasive and water, while the polish- Mountcdfor movement beneath the series of grinding and polishing machines are the tables or cars 11, 12, 13, 14, etc;, such tables or cars being supported upon theQtrack 8.

These tables or cars are coupled tightly toe gether at their endsso as. to form azcontinuous tram and are driven fromthe spur wheel 15, which engages the racks 16 on the bottoms of the cars. The spur'wheel 15jis driven from one of the-electric motors 16%.16 through the intermediary of suitable reduction gearing, the two motors being'employed in order to guard against a; failure of the driving apparatusin case of accident to'one of the motors:v The tables or cars carry upon their upper surfaces the glass sheets which are to beground and polished. The pressure of the grinding runners upon the glass is regulated by the'levers 17 which supportthe grinding units, the construction following that shown in'the Evans Patent No. 1,577 ,4-57 dated Mar. 23, 1 926.v The position of the levers is;.regulated' by. means of the wheels 18 which are threaded on to the rods 19 pivoted tothe lever 17 at their upper ends.

mg runners are suppliedjwith. a ,mixture of .rouseand water. 7

scars :22, 23.

track 3 is the return track 28.

jupon the transfer car 22 and the table 141 being shown in position upon the transfer car 23. Also extending between the transfer tracks and 21 and parallel to the work The transfer cars are adapted to bebrought into alignment with :this track 28, thus providinggfor the return of the work tables to starting ,po-

sition.

vThe returntrack is preferably enclosed by the side and end walls 29 and'30 and thecars are carried through the chamber, thus provided by meansof an'endless chain 31 pro vided with suitable means :for engaging the cars and moving them to the left (Fig. l).

' lhe top 'wall .30 above the return track provides a convenient storage space for the extra grinder and polisherrunners 32.and 33 and for the glass storage racks 3 1 and 35. {The storage mama preferably handled by :an overhead crane 36 mountedupon the track 7 '37 suchcrane being shown as'transi whichhas'been ground and polished upon one.

porting the rack 36 7 Rough ,glasswhich is :to be .ground and polished is brought into position adjacent the -left hand end of the :track 3 by means of this crane. The racks 34 and 35serve as a storage means for glass side or upon both sides, the glass which has been ground upon both sides being carried awayto the storage room by means of the crane 36.

As heretofore'pointed out, the'work tables 11,12, 13, 1 1, etc. are made in two sets, one

of which has their tops at a slightly lower level than the topsof the other set. This is illustrated in Fig. 4, wherein the table j12has its top surface 37 at a slightly lower level than the surface 38 of the car 13. The glass sheet 40 on the table 12 is one which has'not been ground upon either side, while the sheet tl upon the table 13 has been groundnpon its lower side and is, therefore, slightly thinner than the sheet 40. This difference in thickness of the two sheets is represented by the dimension A, which indicates the difference in the height of the two tables. There- 'fore, when the glass sheets are securedto the tables 'by means of a thin layer of plaster which is of substantially the same thickness in both cases, the upper surfaces of the two sheets 10 and 41 lie at the same level. The space between the adjacent ends ofthe sheets is filled by the plaster of 'Paris 42, so that theltrain of carscarrythe sheetsofaglass as a continuous unbroken surface. By the expedient, as above indicated, glass sheets which have not been ground upon either-side may be surfacedinthesame operation with sheets which have been ground upon one sidewithout disturbing the .-.continuity of the upper surface of the series of sheets. The sheets of different thickness ma-y'alternate, or there may be a number of sheets all of roughglass upon successive tables followed a-series of sheets ground upon-one side upon another series of-tables. Allthatm necessary 18 that the workmen who lay the glasszshall place the-all rough glass uponthe lower tablesand the glass surfaced upon one side upon the higher tables. thetwo sets of cars may be painted different colors, or maybeindentifiedin any other suit able manner.

In operation, the rough glass is brought- In order to avoid mistake,

into position adjacent the left handend of the'track 3by means oftheracks' 36 and the cranes 36 and applied to the cars or tables :1-1, 12, 13, etc. by settingthem in plaster, as heretofore referred to. They are thencarried beneaththe series of grindingandpolis'hing machines, thussur'facing the glass upon its upper side, each table being moved onto the transfer car 23 at the right 'handend of the traek3. From this point, the 'tables'are transferred tothe return'track 28andbrought back to the left hand endofathis track. Here the glass is stripped from the tables and stored upon one of the racks 34, 35, thetable then being placed upon the transfer car 22 and'moved over to theposition shown in Fig. 1, at which'time the table isin positionto bc upon the track 3. At this point, the table is supplied with another sheet of rough glass. The glass sheets from the racks 34 and 35, which have been ground upon one side are removed from these racks and placed upon the higher type of cars, such as the' car 13 (Fig 1) which are also brought intojposition along the return track 28, or along one of the attached'tothe rear end of the trainof cars tracks 4-2, 4-2, 4:2, 12, which are adapted to deliver new cars to the transfer cars 22 and 23. It will be seen that this system provided for the handling of both the rough glass and the glass ground upon one side, as

it arrives at the left hand end of'the track 3;

sothat if this supply .is properly timed, only a "limited amount of glass storage :is required. In fact, it is .noteven necessary to store the glass which is finished upon one side upon the racks '34 and 35,.as the glass maybe'taken directly from the tables on the left hand end.

of the return track 28 and applied directly to the tops of the tables on the work track '3.

that Iclaim is: 1. Apparatus for surfacing plate glass coinprisiug a series of driven grinding andpolishing runners, a traolgl therebeneath, and two sets of cars or tables adapted to form a continuous train and carry on their upper surfaces the sheets of glass to be surfaced, said tables or cars being divided into two sets of fixed levels, with the level of the top surfaces of one set lying at an elevation which is less than that of the level of the top surfaces of the other set by a predetermined distance corresponding to the thickness of glass which is removed from the sheets by the surfacing operation.

2. The method of surfacing plates of glass of two different thicknesses in the same straight away operation which consists in providing two sets of cars or tables adapted to form a continuous faced, said cars or tables being divided into two sets with their upper surfaces at fixed train and carry on their 7 upper surfaces the plates of glass to be sur-v levels, with the level-of the upper surfaces of one set lying at an elevation whichjis less than that of the level of the upper surfaces of the other set by a predetermined distance cor- V responding to the thickness of glass which is removed from the plates by the surfacing operation, placing the plates of glass having one side surfaced on the cars or tables having their upper surfaces at the higher level and plates of glass which have both sides unsurfaced on the cars or tables having their upper sur-- faces at the lower level, and passing the two sets ofcars'thus provided with glass plates in a continuous train beneath a series of grlnding andpolishing runners.

In testimony whereof I have hereunto subscribed my name this 18th day of July, 1927.-

' JOHN H. FOX. 

